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  4. Interesting technique used in some Legacy code!

Interesting technique used in some Legacy code!

Scheduled Pinned Locked Moved The Weird and The Wonderful
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  • OriginalGriffO OriginalGriff

    Well, the good news is it wasn't hidden away in a header file... :omg: If it's any consolation, A FORTRAN compiler I used to work with years, and years ago would accept a constant value as a function parameter, and let you change it at run time. I can't remember FORTRAN syntax any more but it would be similar to:

    void MyMethod (ref int i)
    {
    i = 666;
    }
    ...
    Console.WriteLine(42);
    MyMethod(42);
    Console.WriteLine(42);

    Would happily print: 42 666

    Those who fail to learn history are doomed to repeat it. --- George Santayana (December 16, 1863 – September 26, 1952) Those who fail to clear history are doomed to explain it. --- OriginalGriff (February 24, 1959 – ∞)

    M Offline
    M Offline
    Marco Bertschi
    wrote on last edited by
    #9

    You surely meant to write

    void MyMethod (const int i)
    {
    i = 666;
    }

    The console is a black place

    OriginalGriffO 1 Reply Last reply
    0
    • OriginalGriffO OriginalGriff

      Well, the good news is it wasn't hidden away in a header file... :omg: If it's any consolation, A FORTRAN compiler I used to work with years, and years ago would accept a constant value as a function parameter, and let you change it at run time. I can't remember FORTRAN syntax any more but it would be similar to:

      void MyMethod (ref int i)
      {
      i = 666;
      }
      ...
      Console.WriteLine(42);
      MyMethod(42);
      Console.WriteLine(42);

      Would happily print: 42 666

      Those who fail to learn history are doomed to repeat it. --- George Santayana (December 16, 1863 – September 26, 1952) Those who fail to clear history are doomed to explain it. --- OriginalGriff (February 24, 1959 – ∞)

      Kornfeld Eliyahu PeterK Offline
      Kornfeld Eliyahu PeterK Offline
      Kornfeld Eliyahu Peter
      wrote on last edited by
      #10

      OriginalGriff wrote:

      I can't remember FORTRAN syntax any more

      Getting old?!

      I'm not questioning your powers of observation; I'm merely remarking upon the paradox of asking a masked man who he is. (V)

      "It never ceases to amaze me that a spacecraft launched in 1977 can be fixed remotely from Earth." ― Brian Cox

      OriginalGriffO 1 Reply Last reply
      0
      • M Marco Bertschi

        You surely meant to write

        void MyMethod (const int i)
        {
        i = 666;
        }

        The console is a black place

        OriginalGriffO Offline
        OriginalGriffO Offline
        OriginalGriff
        wrote on last edited by
        #11

        No, that implies the wrong thing. The compiler stored all it's constant values in memory locations, so it could happily pass a reference (or more accurately in those days a machine code pointer) to a constant value and it would act like a variable. Total PITA to debug when you met it for the first time: and a hanging offence to leave in production code...

        Those who fail to learn history are doomed to repeat it. --- George Santayana (December 16, 1863 – September 26, 1952) Those who fail to clear history are doomed to explain it. --- OriginalGriff (February 24, 1959 – ∞)

        "I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
        "Common sense is so rare these days, it should be classified as a super power" - Random T-shirt

        F C 2 Replies Last reply
        0
        • Kornfeld Eliyahu PeterK Kornfeld Eliyahu Peter

          OriginalGriff wrote:

          I can't remember FORTRAN syntax any more

          Getting old?!

          I'm not questioning your powers of observation; I'm merely remarking upon the paradox of asking a masked man who he is. (V)

          OriginalGriffO Offline
          OriginalGriffO Offline
          OriginalGriff
          wrote on last edited by
          #12

          I haven't used it for years - and archive retrieval is a lot slower than online storage! :laugh:

          Those who fail to learn history are doomed to repeat it. --- George Santayana (December 16, 1863 – September 26, 1952) Those who fail to clear history are doomed to explain it. --- OriginalGriff (February 24, 1959 – ∞)

          "I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
          "Common sense is so rare these days, it should be classified as a super power" - Random T-shirt

          B 1 Reply Last reply
          0
          • OriginalGriffO OriginalGriff

            I haven't used it for years - and archive retrieval is a lot slower than online storage! :laugh:

            Those who fail to learn history are doomed to repeat it. --- George Santayana (December 16, 1863 – September 26, 1952) Those who fail to clear history are doomed to explain it. --- OriginalGriff (February 24, 1959 – ∞)

            B Offline
            B Offline
            Bernhard Hiller
            wrote on last edited by
            #13

            OriginalGriff wrote:

            archive retrieval

            Magnetic tape at 300 baud? Does the tape reader still work with current Windows?

            OriginalGriffO 1 Reply Last reply
            0
            • D DeathByChocolate

              This was at the top of the code:

              #define 300 1
              #define 100 0

              I'm amazed that the compiler even accepted it! :rolleyes:

              "State acheived after eating too many chocolate-covered coconut bars - bountiful" Chris C-B

              B Offline
              B Offline
              Bernhard Hiller
              wrote on last edited by
              #14

              As a side-effect, wouldn't it change 30000 to 0 via 30000 -> 100 -> 0?

              1 Reply Last reply
              0
              • D DeathByChocolate

                This was at the top of the code:

                #define 300 1
                #define 100 0

                I'm amazed that the compiler even accepted it! :rolleyes:

                "State acheived after eating too many chocolate-covered coconut bars - bountiful" Chris C-B

                P Offline
                P Offline
                phil o
                wrote on last edited by
                #15

                What happens then when you try to divide a number by 100? Just curious ^^

                There are two kinds of people in the world: those who separate humankind in two distinct categories, and those who don't. "I have two hobbies: breasts." DSK

                D 1 Reply Last reply
                0
                • B Bernhard Hiller

                  OriginalGriff wrote:

                  archive retrieval

                  Magnetic tape at 300 baud? Does the tape reader still work with current Windows?

                  OriginalGriffO Offline
                  OriginalGriffO Offline
                  OriginalGriff
                  wrote on last edited by
                  #16

                  I wish! This is the long term storage between my ears we are talking about here... :laugh: I just wish I could find a way to re-index it occasionally ;)

                  Those who fail to learn history are doomed to repeat it. --- George Santayana (December 16, 1863 – September 26, 1952) Those who fail to clear history are doomed to explain it. --- OriginalGriff (February 24, 1959 – ∞)

                  "I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
                  "Common sense is so rare these days, it should be classified as a super power" - Random T-shirt

                  1 Reply Last reply
                  0
                  • P phil o

                    What happens then when you try to divide a number by 100? Just curious ^^

                    There are two kinds of people in the world: those who separate humankind in two distinct categories, and those who don't. "I have two hobbies: breasts." DSK

                    D Offline
                    D Offline
                    DeathByChocolate
                    wrote on last edited by
                    #17

                    I guess, if you did try to do that, you would get a 'divide by 0 error'. Fortunately its only a small project and neither 100 or 300 were ever used as absolute values. It loaded a int with either 300 or 100 (ie 0 or 1) then later it checked to see if that int was equal to 300 or 100 (ie 0 or 1), so it did work but not a technique I would recommend! :rolleyes: :-D

                    "State acheived after eating too many chocolate-covered coconut bars - bountiful" Chris C-B

                    P 1 Reply Last reply
                    0
                    • D DeathByChocolate

                      I guess, if you did try to do that, you would get a 'divide by 0 error'. Fortunately its only a small project and neither 100 or 300 were ever used as absolute values. It loaded a int with either 300 or 100 (ie 0 or 1) then later it checked to see if that int was equal to 300 or 100 (ie 0 or 1), so it did work but not a technique I would recommend! :rolleyes: :-D

                      "State acheived after eating too many chocolate-covered coconut bars - bountiful" Chris C-B

                      P Offline
                      P Offline
                      phil o
                      wrote on last edited by
                      #18

                      Me neither :)

                      There are two kinds of people in the world: those who separate humankind in two distinct categories, and those who don't. "I have two hobbies: breasts." DSK

                      1 Reply Last reply
                      0
                      • OriginalGriffO OriginalGriff

                        No, that implies the wrong thing. The compiler stored all it's constant values in memory locations, so it could happily pass a reference (or more accurately in those days a machine code pointer) to a constant value and it would act like a variable. Total PITA to debug when you met it for the first time: and a hanging offence to leave in production code...

                        Those who fail to learn history are doomed to repeat it. --- George Santayana (December 16, 1863 – September 26, 1952) Those who fail to clear history are doomed to explain it. --- OriginalGriff (February 24, 1959 – ∞)

                        F Offline
                        F Offline
                        Freak30
                        wrote on last edited by
                        #19

                        Changing the value of a literal for subsequent uses of the same literal is pure evil. Who could have ever thought, it was a good idea to implement constants that way? :omg: Was it possibly done to keep the image size of the executable small?

                        The good thing about pessimism is, that you are always either right or pleasently surprised.

                        OriginalGriffO 1 Reply Last reply
                        0
                        • F Freak30

                          Changing the value of a literal for subsequent uses of the same literal is pure evil. Who could have ever thought, it was a good idea to implement constants that way? :omg: Was it possibly done to keep the image size of the executable small?

                          The good thing about pessimism is, that you are always either right or pleasently surprised.

                          OriginalGriffO Offline
                          OriginalGriffO Offline
                          OriginalGriff
                          wrote on last edited by
                          #20

                          Probably - everything was kept small in those days: we didn't have anywhere near as much disk space as you do cache! If I remember rightly, it was a GEC4070[^] - so the main memory would have been 512Kb - and a dozen users using it...

                          Those who fail to learn history are doomed to repeat it. --- George Santayana (December 16, 1863 – September 26, 1952) Those who fail to clear history are doomed to explain it. --- OriginalGriff (February 24, 1959 – ∞)

                          "I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
                          "Common sense is so rare these days, it should be classified as a super power" - Random T-shirt

                          1 Reply Last reply
                          0
                          • OriginalGriffO OriginalGriff

                            Well, the good news is it wasn't hidden away in a header file... :omg: If it's any consolation, A FORTRAN compiler I used to work with years, and years ago would accept a constant value as a function parameter, and let you change it at run time. I can't remember FORTRAN syntax any more but it would be similar to:

                            void MyMethod (ref int i)
                            {
                            i = 666;
                            }
                            ...
                            Console.WriteLine(42);
                            MyMethod(42);
                            Console.WriteLine(42);

                            Would happily print: 42 666

                            Those who fail to learn history are doomed to repeat it. --- George Santayana (December 16, 1863 – September 26, 1952) Those who fail to clear history are doomed to explain it. --- OriginalGriff (February 24, 1959 – ∞)

                            M Offline
                            M Offline
                            mikepwilson
                            wrote on last edited by
                            #21

                            Oh that's some exciting crap right there.

                            1 Reply Last reply
                            0
                            • D DeathByChocolate

                              This was at the top of the code:

                              #define 300 1
                              #define 100 0

                              I'm amazed that the compiler even accepted it! :rolleyes:

                              "State acheived after eating too many chocolate-covered coconut bars - bountiful" Chris C-B

                              S Offline
                              S Offline
                              Super Lloyd
                              wrote on last edited by
                              #22

                              You forgot ;P

                              #define true 0
                              #define false 1
                              #define maybe true

                              My programming get away... The Blog... DirectX for WinRT/C# since 2013! Taking over the world since 1371!

                              S 1 Reply Last reply
                              0
                              • OriginalGriffO OriginalGriff

                                No, that implies the wrong thing. The compiler stored all it's constant values in memory locations, so it could happily pass a reference (or more accurately in those days a machine code pointer) to a constant value and it would act like a variable. Total PITA to debug when you met it for the first time: and a hanging offence to leave in production code...

                                Those who fail to learn history are doomed to repeat it. --- George Santayana (December 16, 1863 – September 26, 1952) Those who fail to clear history are doomed to explain it. --- OriginalGriff (February 24, 1959 – ∞)

                                C Offline
                                C Offline
                                cpkilekofp
                                wrote on last edited by
                                #23

                                Geez, I have never actually seen an example of this, but our Fortran and Data Structures instructor mentioned it once on a really old version of Fortran IV.

                                "Seize the day" - Horace "It's not what he doesn't know that scares me; it's what he knows for sure that just ain't so!" - Will Rogers, said by him about Herbert Hoover

                                OriginalGriffO 1 Reply Last reply
                                0
                                • C cpkilekofp

                                  Geez, I have never actually seen an example of this, but our Fortran and Data Structures instructor mentioned it once on a really old version of Fortran IV.

                                  "Seize the day" - Horace "It's not what he doesn't know that scares me; it's what he knows for sure that just ain't so!" - Will Rogers, said by him about Herbert Hoover

                                  OriginalGriffO Offline
                                  OriginalGriffO Offline
                                  OriginalGriff
                                  wrote on last edited by
                                  #24

                                  You're just trying to make me feel old, aren't you? Well it won't work, I tell you! I have a wife who has that job covered... :sigh:

                                  Those who fail to learn history are doomed to repeat it. --- George Santayana (December 16, 1863 – September 26, 1952) Those who fail to clear history are doomed to explain it. --- OriginalGriff (February 24, 1959 – ∞)

                                  "I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
                                  "Common sense is so rare these days, it should be classified as a super power" - Random T-shirt

                                  1 Reply Last reply
                                  0
                                  • S Super Lloyd

                                    You forgot ;P

                                    #define true 0
                                    #define false 1
                                    #define maybe true

                                    My programming get away... The Blog... DirectX for WinRT/C# since 2013! Taking over the world since 1371!

                                    S Offline
                                    S Offline
                                    Stefan_Lang
                                    wrote on last edited by
                                    #25

                                    Super Lloyd wrote:

                                    #define true 0
                                    #define false 1
                                    #define maybe true || false

                                    FTFY ;P

                                    GOTOs are a bit like wire coat hangers: they tend to breed in the darkness, such that where there once were few, eventually there are many, and the program's architecture collapses beneath them. (Fran Poretto)

                                    S 1 Reply Last reply
                                    0
                                    • S Stefan_Lang

                                      Super Lloyd wrote:

                                      #define true 0
                                      #define false 1
                                      #define maybe true || false

                                      FTFY ;P

                                      GOTOs are a bit like wire coat hangers: they tend to breed in the darkness, such that where there once were few, eventually there are many, and the program's architecture collapses beneath them. (Fran Poretto)

                                      S Offline
                                      S Offline
                                      Super Lloyd
                                      wrote on last edited by
                                      #26

                                      Much better way of defining maybe, love it! :-D

                                      My programming get away... The Blog... DirectX for WinRT/C# since 2013! Taking over the world since 1371!

                                      1 Reply Last reply
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